I thought of a real world example for aura.
Take a couple candles, each has it's own flame.
Put them a few inches away from each other and put your hand between them.
You feel heat from both sides, no matter how big your hand is.
The heat can only heat up a certain part of your hand, the part that is closest to the flame.
If you were to have the candles very close to each other, maybe even stacked on top of each other (the same space)
The heat would feel hotter and it would heat you more.
You may not be able to tell the difference, but they are from seperate sources and give you more heat total.